Selectrive switch



Aug. 28, 1951 G. DEAKIN SELECTIVE SWITCH 4 Sheets-Sheet 1 Filed Sept. 14, 1946 m V w i" J I N V EN TOR. (Sf/P440 054M v fi- ATT'ORIVE'Y Aug. 28, 1951 G. DEAKIN ,4

SELECTIVE SWITCH Filed Sept. 14, 1946 4 Sheets-Sheet 2 A T TUBA Z Y Aug. 28, 1951 G. DEAKIN SELECTIVE SWITCH 4 Sheets-Sheet 5 Filed Sept. 14, 1946 'filIlllllll'l u n I INVENTOR. 65/?1410 0514A //V ATTORNEY Aug. 28, 1951 DEAKlN 2,565,480

SELECTIVE SWITCH I Filed Sept. 14, 1946 4 Sheets-Sheet 4 I N V EN TOR. 615F141 D DEHK/IV Patented Aug. 28, 1951 UNITED STATES SELECTIVE SWITCH Gerald Deakin, New York, N. Y., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application September 14, 1946, Serial No. 697,148

6 Claims. 1

This invention relates to circuit controlling apparatus, and particularly to circuit controllers for successive operation of circuits of the multiplied type, such as are required in automatic telephone systems.

An object of the invention is to provide an improved circuit closing mechanism of the type in which a brush carriage is caused to travel along a bank of terminal projections engaged sequentially by carriage brushes, which brushes also maintain constant engagement with current feeder strips corresponding in number to the number of rows of terminal projections in the terminal bank.

The use, in automatic telephone systems, of brush carriages traveling at fairly high speed across large numbers of separate, but closely spaced, terminal projections of relatively fine structure, creates certain problems, one of which is the problem of vibration. Due to the extensive area of the terminal bank, and the relatively great distance between end supports for the rods upon which the carriage is suspended, there is a tendency of the parts to vibrate both horizontally and vertically. Building vibrations, if present, aggravate this condition. The resulting vibration of traveling brushes and terminal contacts, engaged by the brushes as they travel, introduces resistance variables into the circuits controlled by these parts. If any of these circuits carry speech currents, there is a corresponding variable introduced into the speech transmission, with a consequent impairment of clarity, volume, or tone, or of all three.

Another problem inherent in carriage and combinations is the problem of contact fouling, as by atmosphere-induced corrosion, or by reason of lodgment of dust, dirt, or other foreign particles on the feeder strips, or on the strip eneaging surfaces of the brushes traveling along these strips. Such corrosion or foreign matter is just as detrimental as vibration, and produces the same difiiculty, namely, a variation in circuit resistance and a resultant impairment of the quality of speech transmission.

To meet the problem of vibration, the present invention includes novel mounting and supporting means for cushioning the connections (a) between the brush assembly and its carriage, and (1)) between the feeder strips and their end supports; the disclosed cushioning means being of a character adapted to provide effective vibration clamping at the points indicated and thus eliminate or at least reduce to a negligible minimum the transmission of such vibrations into the speech circuits of the system.

PATENT OFFICE Pill-"27.53) 2 To meet the problem of contact fouling, the present invention includes a novel construction and inter-relationship of brushes and feeder strips, which novel construction and inter-relationship renders the parts self-cleaning in actual operation, thus removing substantially all possibility of prolonged impairment of the contact surfaces of the strip engagin brushes, by either foreign matter or corrosion.

Objects of the invention, therefore, are to improve the mounting and supporting mechanism in a device of the character indicated, also to improve the quality of speech and signal transmission by removing, or at least minimizthe possibility of contact deterioration.

Another object is to provide an improved brush assembly, characterized by reduction in the number of component parts and greater simplicity in their structure and method of manufacture and application; also by the greater ciliciency of their operation, and their greater serviccab ity. In this connection further features of the invention are the novel arrangement of the brush retaining means, the novel construe-- tion and contour of the brushes themselves, re sulting in definite advantages as hereinafter more fully developed.

The above other objects and features of the invention will be better understood upon examination of the following description and reference to the accompanying drawings illustrating the invention as embodied in automatic switching equipment of a type now deemed most s iitable for the stated purposes; there being also itrated certain modifications of some of the component parts. The drawings show only so much of a complete system as is adequate for explanation of the invention.

In these drawings:

Fig. 1 is a plan view of a brush carriage and supporting structure therefore, and showing also one of a series of feeder strips, together with supporting structure;

Figs. 2, 3, and 4 are views along lines 2-2, 3-3, and 4-4, respectively, of Fig. 1;

Fig. 5 is a view, on an enlarged scale, of one of the several brush units entering into a complete brush assembly;

Figs. 6 and 7 show the brush unit of Fig. 5, as viewed from other angles;

Figs. 8 and 8A are sectional views along lines 8 and 8A, respectively, of Fig. 5;

Figs. 9, 10, and 11 show a modified form of brush unit, as viewed from three sides;

Fig. '12 is a sectional view along line |2l2 of Fig. 9;

Figs. 13, 14, and 15 are plan and opposite end views, respectively, of a brush holder; and

Fig. 16 is a perspective view showing the novel carriage mounts.

Referring first to Figs. 1 to 4, the reference numerals I5 and I6 designate end supports for a pair of parallel rods I1 and I8; the said end supports having bosses I9 for reception of the rod ends (held therein by set-screws 2|) and also having flanges 22 for anchorage on a channelpiece or other rigid portion of the carrying structure, (bay) not shown. Each rod I'I, I8 carries a pair of bearings 23 to which are secured arms 24 constituting parallel extensions of a U-shaped strap 26 forming an integrated part of the boxlike brush carriage chassis 2'I. Opposite corners of the carriage chassis 21, shown best in Fig. 16, areprovided with flaps 28, 29 to serve as guides for positioning the vibration-damping mounting means hereinafter described more fully.

The brush assembly includes a series of brush units, each of which travels along a row of terminal contacts 35 of the contact bank, and is operative to establish current conducting relationship between such contacts, successively, and a feeder strip 3| located on the same side of the switching bay, at the same horizontal level as that occupied by the corresponding row of terminal contacts. In the illustrated embodiment of the invention, there are eight brush units in the brush assembly, divided into two sets of four units each, (see Fig. 4) and a corresponding number of feeder strips 3| (see Figs. 2, 3 and 4) similarly divided, so that each brush unit has an end portion riding continuously on its individual feeder strip as the brush carriage travels along the rods II, I8 in opposite directions alternately, under the impetus of conventional power driving means, not shown.

As shown in Figs. 5 to 8A, each brush unit is composed of two distinct complementary segments 32, 33 of suitably tempered spring material as, for example, Phosphor bronze, and each complementary segment is centrally depressed and laterally extended, forming tabs 36, 31, on one segment in juxtaposed relationship to the corresponding tabs 38, 39, of the complementary segment. Backing strips II, 42 cover these tabs, and are in turn retained in the non-conducting brush holder 43 with which each brush unit is individually provided; the novel retaining means consisting of hairpin-shaped clamping springs 44 covering the end portions of the backing strips M, 42 and also pressing resiliently against the sides of ribs 46 (see Fig. 8A) integrally formed on adjacent parts of each brush holder 43. Thus each brush unit is effectively retained and positioned in its individual insulating holder. The several units comprising the complete brush assembly are in turn retained in assembled relationship in the brush carriage chassis 2'! by the novel vibration-absorbing means hereinafter more fully described.

The central depressions formed in the brush complements, as above noted, have the advantage of allowing wider movement of the working end portions of the brushes, without introducing any substantial variation in brush tension. Additionally, the brush complements are preferably edge-turned along their sloping edges, as indicated at 5| and 52 in Figs. 5 and 8, as this stiffening trea.;ment protects the parts against bowing or warping, and insures maintenance of firm contact pressure upon the stationary circuit parts engaged by the brush ends. The latter are preferably sliver-coated along the engaging surfaces, to the degree indicated by the slanting dash lines 53, 54 in Fig. 5; this coating material being preferably applied as an inlay. The brush construction and contour are such as to facilitate production of the brush elements on a multi-slide stamping machine operating upon a continuous strip of metal of selected width, to effect blanking, forming, and tensioning of the brush elements in one continuous series of operations.

The tensioning of the brush elements is such as urge their tips 56 firmly against opposite sides of the particular feeder strip 3i engaged thereby, and to urge their tips 51 firmly against opposite sides of the terminal contacts 35 engaged thereby in succession as the brush carriage traverses its prescribed path of travel.

To bring about the desired Vibration-damping mounting of the present invention, rectangular blocks 6|, 62 (Fig. 16) are provided at opposite sides of the brush carriage chassis, the said blocks being of natural or synthetic rubbery material (neoprene being an example thereof) and of a length and width suitable for their proper registry, first with the trunnions 63 projecting from opposite ends of each brush holder-the blocks 62 being apertured, as shown at 64, to receive said trunnions-and secondly, with the space between flaps 28, 29 on the carriage chassis. Each lock is secured to the chassis by a spring clamp 65 having a lip 67 to engage a flange 68 of the chassis, and an opposite lip fi extending around an'edge of the chassis. The effectiveness of this arrangement as a vibration-damping support for the brush assembly, as well as its simplicity, can readily be understood from this illustration and description of this presently preferred embodimerit.

The desired vibration-damping mounting of the feeder strips 3| is shown in Fig. 1 as including a pair of washers II, 12 of neoprene or the like, and a bushing E3 of similar material, all surrounding the shanl; of a screw 74 by which the end plate 16, of insulating material, is secured to bosses ll of the end support I5. Metal washers "i8 and i9 cover the washers II and I2, respectively, at opposit sides of the central bushing 73, the latter extending through an aperture in the end plate '15. The arrangement is duplicated as to each screw M and as to opposite end plate BI, as indicated at 82 in Figs. 1 and 2. As the feeder strips 35 have tip portions 83, 84 at their opposite ends for retention in apertures in the said end plates "EB, M respectively, as shown in Figs. 1 and 2, and as the said end plates are cushioned in the manner just described, it will be apparent that vibrations in both the longitudinal and transverse directions are effectively absorbed.

To bring about the protection of the working parts of the switch mechanism against objectional contact fouling, the feeder strips 3| are slotted as indicated at 86 and 8'! in Fig. l, the slots 8'8 being slanted in one direction and the slots 8'! oppositely slanted. Any metal particles or foreign matter which the brush tips encounter, as they move along their feeder strip, are pushed into the succeeding slot, and thus fall clear of the entire mechanism. At the end of travel in each direction the brush tips ride off the strip momentarily, and in returning thereto they necessarily encounter slight interference at the curb or 89, as the case may be, due to the slight sagging of the brushes when off the strip. This slight interference, and the consequent climbing of the brushes over the said curb edge 88, or 89, provides opportunity for a scraping and cleaning action as between the brush flanges, on the one hand, and the strip edge on the other. As the slots 85 and 87 are narrower than the span of each brush tip, there is no vibration induced by such slots as the brushes pass over them, but there is a definite cleaning action by reason of the dirt disposal effect afforded thereby. The slanting of the slots makes possible the provision of maximum slot area without unduly enlarging the width of slot along the direct line of brush motion.

In addition to end plates 16 and 8|, intermediate ties 9 l 92 may be provided to assist in holding the feeder strips in properly spaced relationship; these ties being slotted for insertion into recesses in the feeder strips, and held therein by retainer pieces 93, 94, respectively.

Figs. 9 to 12 show a modified type of brush unit utilizing the same form of two-part brush, but a different form of backing, spacing and clamping means therefore, consisting of backing strips [4! and I42, spacers I43, and clamping eyelets I44 to clamp the spring tabs and backing strips in assembled relationship; the strips MI and I42 having lateral extensions l5l, I52 to grip and hold said spacers I43 to the assembly, and longitudinal extensions 163 to fit into the apertures 64 (Fig. 16) of the cushioned blocks 6!, 62, as do the corresponding extensions 63 of insulator 43 of Figs. 13 to 15. It will be noted that the parts l4l, I42, I43, I44 and I63 of Figs. 9 to 12 are substantially comparable in functions to parts 4|, 42, 43, 44 and 63 respectively, of Figs. 5 to 8. Accordingly, if desired, the assembly of Figs. 9 to 12 may be substituted for that of Figs. 5 to 8.

In comparable manner, other substitutions and rearrangements of parts, as well as modifications in the mode of operation, may be resorted to without deviating from the principles of the invention, as herein indicated.

What I claim is:

1. In a device of the class described, a series of terminal contacts, a feeder element, and a commutating brush operating between said feeder element and said series of contacts, said feeder element having a first series of slots slanted in one direction and a second series oppositely slanted, to facilitate quick expulsion of foreign matter lodging in the traversed path of said brush.

2. In a device of the class described, a bank of terminal contacts, a plurality of feeder elements, a plurality of commutating brushes having two complementary segments being operative between said terminal contacts and said feeder elements, an extreme end of each of said two complementary elements contacting said terminal contacts and the other extreme end of each of said segments contacting said feeder element, a single brush carriage embracing all of said brushes, and a shock absorbing mounting between said brushes and carriage.

3. In a device of the class described, a bank of terminal contacts, a guide rail extending along said bank of contacts, in spaced relation thereto, a carriage reciprocable on said guide rail, said carriage having resilient rail members mounted therein, commutating brushes of resilient material each having two complementary segments held in predetermined relationship, said commutating brushes being mounted on said resilient members in said carriage and operable to sequentially engage said bank of terminal contacts.

4. In a device of the class described a bank of terminal contacts, a plurality of feeder strips for electrical coaction with said contacts, said strips being resiliently supported and slotted, a carriage movable in a path adjacent said contacts and feeder strips, shock absorbing mountings in said carriage, a plurality of brush holding elements having trunnions for contacting said shock absorbing mountings, and a plurality of commutating brushes supported by said elements for contacting said plurality of feeder strips and said terminal contacts in response to the traverse motion of said carriage.

5. A device as defined in claim 2, and in which the brushes have members extending at the sides thereof and the shock absorbing mounting comprises blocks of resilient material attached to opposite sides of the carriage and having holes for receiving said members for supporting the brushes between said blocks.

6. A selector switch comprising a series of terminal contacts arranged in substantial alignment, an elongated feeder element substantially parallel to said series of contacts, a commutating brush having two complementary segments, said brush operative between said feeder element and said series of contacts, each of said complementary segments having a mid-point thereof in contiguous relationship to the mid-point of the other segment, the ends of each complementary segment being resiliently urged towards the corresponding ends of the other segment so as to engage opposite sides of said contacts at one end of the brush and opposite sides of the feeder bar at the other end of the brush, a carriage for said brush, means for mounting said carriage for movement substantially parallel to said series of contacts, and means for resiliently mounting said brush on said carriage at substantially the midpoint of said complementary segments, whereby the commutating action between the brush and contacts as said contacts are successively en-' gaged by said brush in response to the traversing motion of said carriage is improved.

GERALD DEAKIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,091,765 Reynolds Mar. 31, 1914 1,558,822 Baker Oct. 27, 1925 1,634,007 Aldendorff June 28, 1927 1,882,981 Schreiber et al Oct. 18, 1932 1,954,092 Muller Apr. 10, 1934 1,954,121 Doring Apr. 10, 1934 2,123,229 Carpenter July 12, 1938 2,173,548 Carpenter Sept. 19, 1938 2,263,804 Gurney Nov. 25, 1941 2,266,156 Brauer Dec. 16, 1941 2,359,605 Ballou Oct. 3, 1944 FOREIGN PATENTS Number Country Date 526,548 Germany June 6, 1931 

